[MergeICmps] Make the pass compatible with the new pass manager.

[courbet]

Thanks.

llvm/include/llvm/InitializePasses.h

 void initializeMemCpyOptLegacyPassPass(PassRegistry&);
 void initializeMemDepPrinterPass(PassRegistry&);
 void initializeMemDerefPrinterPass(PassRegistry&);
 void initializeMemoryDependenceWrapperPassPass(PassRegistry&);
 void initializeMemorySSAPrinterLegacyPassPass(PassRegistry&);
 void initializeMemorySSAWrapperPassPass(PassRegistry&);
 void initializeMemorySanitizerLegacyPassPass(PassRegistry&);
 void initializeMergeFunctionsPass(PassRegistry&);
-void initializeMergeICmpsPass(PassRegistry&);
+void initializeMergeICmpsLegacyPassPass(PassRegistry &);
 void initializeMergedLoadStoreMotionLegacyPassPass(PassRegistry&);
 void initializeMetaRenamerPass(PassRegistry&);
 void initializeModuleDebugInfoPrinterPass(PassRegistry&);
 void initializeModuleSummaryIndexWrapperPassPass(PassRegistry&);
 void initializeMustExecutePrinterPass(PassRegistry&);
 void initializeNameAnonGlobalLegacyPassPass(PassRegistry&);
 void initializeNaryReassociateLegacyPassPass(PassRegistry&);
 void initializeNewGVNLegacyPassPass(PassRegistry&);

llvm/include/llvm/LinkAllPasses.h

ForcePassLinking() {
       (void) llvm::createMemCpyOptPass();
       (void) llvm::createLoopDeletionPass();
       (void) llvm::createPostDomTree();
       (void) llvm::createInstructionNamerPass();
       (void) llvm::createMetaRenamerPass();
       (void) llvm::createPostOrderFunctionAttrsLegacyPass();
       (void) llvm::createReversePostOrderFunctionAttrsPass();
       (void) llvm::createMergeFunctionsPass();
-      (void) llvm::createMergeICmpsPass();
+      (void) llvm::createMergeICmpsLegacyPass();
       (void) llvm::createExpandMemCmpPass();
       std::string buf;
       llvm::raw_string_ostream os(buf);
       (void) llvm::createPrintModulePass(os);
       (void) llvm::createPrintFunctionPass(os);
       (void) llvm::createPrintBasicBlockPass(os);
       (void) llvm::createModuleDebugInfoPrinterPass();
       (void) llvm::createPartialInliningPass();

llvm/include/llvm/Transforms/Scalar.h

 // LowerWidenableCondition - Lower widenable condition to i1 true.
 //
 Pass *createLowerWidenableConditionPass();
 
 //===----------------------------------------------------------------------===//
 //
 // MergeICmps - Merge integer comparison chains into a memcmp
 //
-Pass *createMergeICmpsPass();
+Pass *createMergeICmpsLegacyPass();
 
 //===----------------------------------------------------------------------===//
 //
 // ValuePropagation - Propagate CFG-derived value information
 //
 Pass *createCorrelatedValuePropagationPass();
 
 //===----------------------------------------------------------------------===//

llvm/include/llvm/Transforms/Scalar/MergeICmps.h

+//===- MergeICmps.h -----------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_MERGEICMPS_H
+#define LLVM_TRANSFORMS_SCALAR_MERGEICMPS_H
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+class Function;
+
+struct MergeICmpsPass
+    : PassInfoMixin<MergeICmpsPass> {
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_SCALAR_MERGEICMPS_H

llvm/lib/CodeGen/TargetPassConfig.cpp

void TargetPassConfig::addIRPasses() {
   }
 
   if (getOptLevel() != CodeGenOpt::None) {
     // The MergeICmpsPass tries to create memcmp calls by grouping sequences of
     // loads and compares. ExpandMemCmpPass then tries to expand those calls
     // into optimally-sized loads and compares. The transforms are enabled by a
     // target lowering hook.
     if (!DisableMergeICmps)
-      addPass(createMergeICmpsPass());
+      addPass(createMergeICmpsLegacyPass());
     addPass(createExpandMemCmpPass());
   }
 
   // Run GC lowering passes for builtin collectors
   // TODO: add a pass insertion point here
   addPass(createGCLoweringPass());
   addPass(createShadowStackGCLoweringPass());
 

llvm/lib/Passes/PassBuilder.cpp

 #include "llvm/Transforms/Scalar/LoopUnrollPass.h"
 #include "llvm/Transforms/Scalar/LowerAtomic.h"
 #include "llvm/Transforms/Scalar/LowerExpectIntrinsic.h"
 #include "llvm/Transforms/Scalar/LowerGuardIntrinsic.h"
 #include "llvm/Transforms/Scalar/LowerWidenableCondition.h"
 #include "llvm/Transforms/Scalar/MakeGuardsExplicit.h"
 #include "llvm/Transforms/Scalar/MemCpyOptimizer.h"
 #include "llvm/Transforms/Scalar/MergedLoadStoreMotion.h"
+#include "llvm/Transforms/Scalar/MergeICmps.h"
 #include "llvm/Transforms/Scalar/NaryReassociate.h"
 #include "llvm/Transforms/Scalar/NewGVN.h"
 #include "llvm/Transforms/Scalar/PartiallyInlineLibCalls.h"
 #include "llvm/Transforms/Scalar/Reassociate.h"
 #include "llvm/Transforms/Scalar/RewriteStatepointsForGC.h"
 #include "llvm/Transforms/Scalar/SCCP.h"
 #include "llvm/Transforms/Scalar/SROA.h"
 #include "llvm/Transforms/Scalar/Scalarizer.h"

llvm/lib/Passes/PassRegistry.def

 FUNCTION_PASS("guard-widening", GuardWideningPass())
 FUNCTION_PASS("gvn", GVN())
 FUNCTION_PASS("load-store-vectorizer", LoadStoreVectorizerPass())
 FUNCTION_PASS("loop-simplify", LoopSimplifyPass())
 FUNCTION_PASS("loop-sink", LoopSinkPass())
 FUNCTION_PASS("lowerinvoke", LowerInvokePass())
 FUNCTION_PASS("mem2reg", PromotePass())
 FUNCTION_PASS("memcpyopt", MemCpyOptPass())
+FUNCTION_PASS("mergeicmps", MergeICmpsPass())
 FUNCTION_PASS("mldst-motion", MergedLoadStoreMotionPass())
 FUNCTION_PASS("nary-reassociate", NaryReassociatePass())
 FUNCTION_PASS("newgvn", NewGVNPass())
 FUNCTION_PASS("jump-threading", JumpThreadingPass())
 FUNCTION_PASS("partially-inline-libcalls", PartiallyInlineLibCallsPass())
 FUNCTION_PASS("lcssa", LCSSAPass())
 FUNCTION_PASS("loop-data-prefetch", LoopDataPrefetchPass())
 FUNCTION_PASS("loop-load-elim", LoopLoadEliminationPass())

llvm/lib/Transforms/Scalar/MergeICmps.cpp

 //    bool S::operator==(const S& o) const {
 //      return memcmp(this, &o, 8) == 0;
 //    }
 //
 //  Which will later be expanded (ExpandMemCmp) as a single 8-bytes icmp.
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Transforms/Scalar/MergeICmps.h"
 #include "llvm/Analysis/DomTreeUpdater.h"
 #include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/Analysis/Loads.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
public:
   const BCEAtom &Rhs() const { return Rhs_; }
   int SizeBits() const { return SizeBits_; }
 
   // Returns true if the block does other works besides comparison.
   bool doesOtherWork() const;
 
   // Returns true if the non-BCE-cmp instructions can be separated from BCE-cmp
   // instructions in the block.
-  bool canSplit(AliasAnalysis *AA) const;
+  bool canSplit(AliasAnalysis &AA) const;
 
   // Return true if this all the relevant instructions in the BCE-cmp-block can
   // be sunk below this instruction. By doing this, we know we can separate the
   // BCE-cmp-block instructions from the non-BCE-cmp-block instructions in the
   // block.
   bool canSinkBCECmpInst(const Instruction *, DenseSet<Instruction *> &,
-                         AliasAnalysis *AA) const;
+                         AliasAnalysis &AA) const;
 
   // We can separate the BCE-cmp-block instructions and the non-BCE-cmp-block
   // instructions. Split the old block and move all non-BCE-cmp-insts into the
   // new parent block.
-  void split(BasicBlock *NewParent, AliasAnalysis *AA) const;
+  void split(BasicBlock *NewParent, AliasAnalysis &AA) const;
 
   // The basic block where this comparison happens.
   BasicBlock *BB = nullptr;
   // The ICMP for this comparison.
   ICmpInst *CmpI = nullptr;
   // The terminating branch.
   BranchInst *BranchI = nullptr;
   // The block requires splitting.
   bool RequireSplit = false;
 
 private:
   BCEAtom Lhs_;
   BCEAtom Rhs_;
   int SizeBits_ = 0;
 };
 
 bool BCECmpBlock::canSinkBCECmpInst(const Instruction *Inst,
                                     DenseSet<Instruction *> &BlockInsts,
-                                    AliasAnalysis *AA) const {
+                                    AliasAnalysis &AA) const {
   // If this instruction has side effects and its in middle of the BCE cmp block
   // instructions, then bail for now.
   if (Inst->mayHaveSideEffects()) {
     // Bail if this is not a simple load or store
     if (!isSimpleLoadOrStore(Inst))
       return false;
     // Disallow stores that might alias the BCE operands
     MemoryLocation LLoc = MemoryLocation::get(Lhs_.LoadI);
     MemoryLocation RLoc = MemoryLocation::get(Rhs_.LoadI);
-    if (isModSet(AA->getModRefInfo(Inst, LLoc)) ||
-        isModSet(AA->getModRefInfo(Inst, RLoc)))
-        return false;
+    if (isModSet(AA.getModRefInfo(Inst, LLoc)) ||
+        isModSet(AA.getModRefInfo(Inst, RLoc)))
   }
   // Make sure this instruction does not use any of the BCE cmp block
   // instructions as operand.
   for (auto BI : BlockInsts) {
     if (is_contained(Inst->operands(), BI))
       return false;
   }
   return true;
 }
 
-void BCECmpBlock::split(BasicBlock *NewParent, AliasAnalysis *AA) const {
+void BCECmpBlock::split(BasicBlock *NewParent, AliasAnalysis &AA) const {
   DenseSet<Instruction *> BlockInsts(
       {Lhs_.GEP, Rhs_.GEP, Lhs_.LoadI, Rhs_.LoadI, CmpI, BranchI});
   llvm::SmallVector<Instruction *, 4> OtherInsts;
   for (Instruction &Inst : *BB) {
     if (BlockInsts.count(&Inst))
       continue;
       assert(canSinkBCECmpInst(&Inst, BlockInsts, AA) &&
              "Split unsplittable block");
     // This is a non-BCE-cmp-block instruction. And it can be separated
     // from the BCE-cmp-block instruction.
     OtherInsts.push_back(&Inst);
   }
 
   // Do the actual spliting.
   for (Instruction *Inst : reverse(OtherInsts)) {
     Inst->moveBefore(&*NewParent->begin());
   }
 }
 
-bool BCECmpBlock::canSplit(AliasAnalysis *AA) const {
+bool BCECmpBlock::canSplit(AliasAnalysis &AA) const {
   DenseSet<Instruction *> BlockInsts(
       {Lhs_.GEP, Rhs_.GEP, Lhs_.LoadI, Rhs_.LoadI, CmpI, BranchI});
   for (Instruction &Inst : *BB) {
     if (!BlockInsts.count(&Inst)) {
       if (!canSinkBCECmpInst(&Inst, BlockInsts, AA))
         return false;
     }
   }
LLVM_DEBUG(dbgs() << "Block '" << Comparison.BB->getName()
                     << Comparison.Rhs().Offset << "\n");
   LLVM_DEBUG(dbgs() << "\n");
   Comparisons.push_back(std::move(Comparison));
 }
 
 // A chain of comparisons.
 class BCECmpChain {
  public:
    BCECmpChain(const std::vector<BasicBlock *> &Blocks, PHINode &Phi,
-              AliasAnalysis *AA);
+               AliasAnalysis &AA);
 
    int size() const { return Comparisons_.size(); }
 
 #ifdef MERGEICMPS_DOT_ON
   void dump() const;
 #endif  // MERGEICMPS_DOT_ON
 
-  bool simplify(const TargetLibraryInfo *const TLI, AliasAnalysis *AA,
+  bool simplify(const TargetLibraryInfo &TLI, AliasAnalysis &AA,
                 DomTreeUpdater &DTU);
 
 private:
   static bool IsContiguous(const BCECmpBlock &First,
                            const BCECmpBlock &Second) {
     return First.Lhs().BaseId == Second.Lhs().BaseId &&
            First.Rhs().BaseId == Second.Rhs().BaseId &&
            First.Lhs().Offset + First.SizeBits() / 8 == Second.Lhs().Offset &&
            First.Rhs().Offset + First.SizeBits() / 8 == Second.Rhs().Offset;
   }
 
   PHINode &Phi_;
   std::vector<BCECmpBlock> Comparisons_;
   // The original entry block (before sorting);
   BasicBlock *EntryBlock_;
 };
 
 BCECmpChain::BCECmpChain(const std::vector<BasicBlock *> &Blocks, PHINode &Phi,
-                         AliasAnalysis *AA)
+                         AliasAnalysis &AA)
     : Phi_(Phi) {
   assert(!Blocks.empty() && "a chain should have at least one block");
   // Now look inside blocks to check for BCE comparisons.
   std::vector<BCECmpBlock> Comparisons;
   BaseIdentifier BaseId;
   for (size_t BlockIdx = 0; BlockIdx < Blocks.size(); ++BlockIdx) {
     BasicBlock *const Block = Blocks[BlockIdx];
     assert(Block && "invalid block");
private:
   }
 };
 } // namespace
 
 // Merges the given contiguous comparison blocks into one memcmp block.
 static BasicBlock *mergeComparisons(ArrayRef<BCECmpBlock> Comparisons,
                                     BasicBlock *const InsertBefore,
                                     BasicBlock *const NextCmpBlock,
-                                    PHINode &Phi,
-                                    const TargetLibraryInfo *const TLI,
-                                    AliasAnalysis *AA, DomTreeUpdater &DTU) {
+                                    PHINode &Phi, const TargetLibraryInfo &TLI,
+                                    AliasAnalysis &AA, DomTreeUpdater &DTU) {
   assert(!Comparisons.empty() && "merging zero comparisons");
   LLVMContext &Context = NextCmpBlock->getContext();
   const BCECmpBlock &FirstCmp = Comparisons[0];
 
   // Create a new cmp block before next cmp block.
   BasicBlock *const BB =
       BasicBlock::Create(Context, MergedBlockName(Comparisons).Name,
                          NextCmpBlock->getParent(), InsertBefore);
const unsigned TotalSizeBits = std::accumulate(
         Comparisons.begin(), Comparisons.end(), 0u,
         [](int Size, const BCECmpBlock &C) { return Size + C.SizeBits(); });
 
     // Create memcmp() == 0.
     const auto &DL = Phi.getModule()->getDataLayout();
     Value *const MemCmpCall = emitMemCmp(
         Lhs, Rhs,
         ConstantInt::get(DL.getIntPtrType(Context), TotalSizeBits / 8), Builder,
-        DL, TLI);
+        DL, &TLI);
     IsEqual = Builder.CreateICmpEQ(
         MemCmpCall, ConstantInt::get(Type::getInt32Ty(Context), 0));
   }
 
   BasicBlock *const PhiBB = Phi.getParent();
   // Add a branch to the next basic block in the chain.
   if (NextCmpBlock == PhiBB) {
     // Continue to phi, passing it the comparison result.
     Builder.CreateBr(PhiBB);
     Phi.addIncoming(IsEqual, BB);
     DTU.applyUpdates({{DominatorTree::Insert, BB, PhiBB}});
   } else {
     // Continue to next block if equal, exit to phi else.
     Builder.CreateCondBr(IsEqual, NextCmpBlock, PhiBB);
     Phi.addIncoming(ConstantInt::getFalse(Context), BB);
     DTU.applyUpdates({{DominatorTree::Insert, BB, NextCmpBlock},
                       {DominatorTree::Insert, BB, PhiBB}});
   }
   return BB;
 }
 
-bool BCECmpChain::simplify(const TargetLibraryInfo *const TLI,
-                           AliasAnalysis *AA, DomTreeUpdater &DTU) {
+bool BCECmpChain::simplify(const TargetLibraryInfo &TLI, AliasAnalysis &AA,
+                           DomTreeUpdater &DTU) {
   assert(Comparisons_.size() >= 2 && "simplifying trivial BCECmpChain");
   // First pass to check if there is at least one merge. If not, we don't do
   // anything and we keep analysis passes intact.
   const auto AtLeastOneMerged = [this]() {
     for (size_t I = 1; I < Comparisons_.size(); ++I) {
       if (IsContiguous(Comparisons_[I - 1], Comparisons_[I]))
         return true;
     }
     return false;
   };
   if (!AtLeastOneMerged())
     return false;
 
   LLVM_DEBUG(dbgs() << "Simplifying comparison chain starting at block "
                     << EntryBlock_->getName() << "\n");
 
   // Effectively merge blocks. We go in the reverse direction from the phi block
   // so that the next block is always available to branch to.
-  const auto mergeRange = [this, TLI, AA, &DTU](int I, int Num,
+  const auto mergeRange = [this, &TLI, &AA, &DTU](int I, int Num,
                                                   BasicBlock *InsertBefore,
                                                   BasicBlock *Next) {
     return mergeComparisons(makeArrayRef(Comparisons_).slice(I, Num),
                             InsertBefore, Next, Phi_, TLI, AA, DTU);
   };
   int NumMerged = 1;
   BasicBlock *NextCmpBlock = Phi_.getParent();
   for (int I = static_cast<int>(Comparisons_.size()) - 2; I >= 0; --I) {
     if (IsContiguous(Comparisons_[I], Comparisons_[I + 1])) {
       LLVM_DEBUG(dbgs() << "Merging block " << Comparisons_[I].BB->getName()
if (Phi.getBasicBlockIndex(SinglePredecessor) < 0) {
       return {};
     }
     CurBlock = SinglePredecessor;
   }
   Blocks[0] = CurBlock;
   return Blocks;
 }
 
-bool processPhi(PHINode &Phi, const TargetLibraryInfo *const TLI,
-                AliasAnalysis *AA, DomTreeUpdater &DTU) {
+bool processPhi(PHINode &Phi, const TargetLibraryInfo &TLI, AliasAnalysis &AA,
+                DomTreeUpdater &DTU) {
   LLVM_DEBUG(dbgs() << "processPhi()\n");
   if (Phi.getNumIncomingValues() <= 1) {
     LLVM_DEBUG(dbgs() << "skip: only one incoming value in phi\n");
     return false;
   }
   // We are looking for something that has the following structure:
   //   bb1 --eq--> bb2 --eq--> bb3 --eq--> bb4 --+
   //     \            \           \               \
bool processPhi(PHINode &Phi, const TargetLibraryInfo &TLI, AliasAnalysis &AA,
   if (CmpChain.size() < 2) {
     LLVM_DEBUG(dbgs() << "skip: only one compare block\n");
     return false;
   }
 
   return CmpChain.simplify(TLI, AA, DTU);
 }
 
-class MergeICmps : public FunctionPass {
- public:
+static bool runImpl(Function &F, const TargetLibraryInfo &TLI,
+                    const TargetTransformInfo &TTI, AliasAnalysis &AA,
+                    DominatorTree *DT) {
+  LLVM_DEBUG(dbgs() << "MergeICmpsLegacyPass: " << F.getName() << "\n");
+
+  // We only try merging comparisons if the target wants to expand memcmp later.
+  // The rationale is to avoid turning small chains into memcmp calls.
+  if (!TTI.enableMemCmpExpansion(true))
+    return false;
+
+  // If we don't have memcmp avaiable we can't emit calls to it.
+  if (!TLI.has(LibFunc_memcmp))
+    return false;
+
+  DomTreeUpdater DTU(DT, /*PostDominatorTree*/ nullptr,
+                     DomTreeUpdater::UpdateStrategy::Eager);
+
+  bool MadeChange = false;
+
+  for (auto BBIt = ++F.begin(); BBIt != F.end(); ++BBIt) {
+    // A Phi operation is always first in a basic block.
+    if (auto *const Phi = dyn_cast<PHINode>(&*BBIt->begin()))
+      MadeChange |= processPhi(*Phi, TLI, AA, DTU);
+  }
+
+  return MadeChange;
+}
+
+class MergeICmpsLegacyPass : public FunctionPass {
   static char ID;
 
-  MergeICmps() : FunctionPass(ID) {
-    initializeMergeICmpsPass(*PassRegistry::getPassRegistry());
+  MergeICmpsLegacyPass() : FunctionPass(ID) {
+    initializeMergeICmpsLegacyPassPass(*PassRegistry::getPassRegistry());
   }
 
   bool runOnFunction(Function &F) override {
     if (skipFunction(F)) return false;
     const auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
     const auto &TTI = getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
     // MergeICmps does not need the DominatorTree, but we update it if it's
     // already available.
     auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
-    DomTreeUpdater DTU(DTWP ? &DTWP->getDomTree() : nullptr,
-                       /*PostDominatorTree*/ nullptr,
-                       DomTreeUpdater::UpdateStrategy::Eager);
-    AliasAnalysis *AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
-    auto PA = runImpl(F, &TLI, &TTI, AA, DTU);
-    return !PA.areAllPreserved();
+    auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
+    return runImpl(F, TLI, TTI, AA, DTWP ? &DTWP->getDomTree() : nullptr);
   }
 
  private:
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<TargetLibraryInfoWrapperPass>();
     AU.addRequired<TargetTransformInfoWrapperPass>();
     AU.addRequired<AAResultsWrapperPass>();
     AU.addPreserved<GlobalsAAWrapperPass>();
     AU.addPreserved<DominatorTreeWrapperPass>();
   }
-
-  PreservedAnalyses runImpl(Function &F, const TargetLibraryInfo *TLI,
-                            const TargetTransformInfo *TTI, AliasAnalysis *AA,
-                            DomTreeUpdater &DTU);
 };
 
-PreservedAnalyses MergeICmps::runImpl(Function &F, const TargetLibraryInfo *TLI,
-                                      const TargetTransformInfo *TTI,
-                                      AliasAnalysis *AA, DomTreeUpdater &DTU) {
-  LLVM_DEBUG(dbgs() << "MergeICmpsPass: " << F.getName() << "\n");
-
-  // We only try merging comparisons if the target wants to expand memcmp later.
-  // The rationale is to avoid turning small chains into memcmp calls.
-  if (!TTI->enableMemCmpExpansion(true)) return PreservedAnalyses::all();
-
-  // If we don't have memcmp avaiable we can't emit calls to it.
-  if (!TLI->has(LibFunc_memcmp))
-    return PreservedAnalyses::all();
+} // namespace
 
-  bool MadeChange = false;
+char MergeICmpsLegacyPass::ID = 0;
+INITIALIZE_PASS_BEGIN(MergeICmpsLegacyPass, "mergeicmps",
+                      "Merge contiguous icmps into a memcmp", false, false)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
+INITIALIZE_PASS_END(MergeICmpsLegacyPass, "mergeicmps",
+                    "Merge contiguous icmps into a memcmp", false, false)
 
-  for (auto BBIt = ++F.begin(); BBIt != F.end(); ++BBIt) {
-    // A Phi operation is always first in a basic block.
-    if (auto *const Phi = dyn_cast<PHINode>(&*BBIt->begin()))
-      MadeChange |= processPhi(*Phi, TLI, AA, DTU);
-  }
+Pass *llvm::createMergeICmpsLegacyPass() { return new MergeICmpsLegacyPass(); }
 
-  if (!MadeChange)
+PreservedAnalyses MergeICmpsPass::run(Function &F,
+                                      FunctionAnalysisManager &AM) {
+  auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
+  auto &TTI = AM.getResult<TargetIRAnalysis>(F);
+  auto &AA = AM.getResult<AAManager>(F);
+  auto *DT = AM.getCachedResult<DominatorTreeAnalysis>(F);
+  const bool MadeChanges = runImpl(F, TLI, TTI, AA, DT);
+  if (!MadeChanges)
     return PreservedAnalyses::all();
   PreservedAnalyses PA;
   PA.preserve<GlobalsAA>();
   PA.preserve<DominatorTreeAnalysis>();
   return PA;
 }
-
-}  // namespace
-
-char MergeICmps::ID = 0;
-INITIALIZE_PASS_BEGIN(MergeICmps, "mergeicmps",
-                      "Merge contiguous icmps into a memcmp", false, false)
-INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
-INITIALIZE_PASS_END(MergeICmps, "mergeicmps",
-                    "Merge contiguous icmps into a memcmp", false, false)
-
-Pass *llvm::createMergeICmpsPass() { return new MergeICmps(); }

llvm/lib/Transforms/Scalar/Scalar.cpp

void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeWarnMissedTransformationsLegacyPass(Registry);
   initializeLoopVersioningLICMPass(Registry);
   initializeLoopIdiomRecognizeLegacyPassPass(Registry);
   initializeLowerAtomicLegacyPassPass(Registry);
   initializeLowerExpectIntrinsicPass(Registry);
   initializeLowerGuardIntrinsicLegacyPassPass(Registry);
   initializeLowerWidenableConditionLegacyPassPass(Registry);
   initializeMemCpyOptLegacyPassPass(Registry);
-  initializeMergeICmpsPass(Registry);
+  initializeMergeICmpsLegacyPassPass(Registry);
   initializeMergedLoadStoreMotionLegacyPassPass(Registry);
   initializeNaryReassociateLegacyPassPass(Registry);
   initializePartiallyInlineLibCallsLegacyPassPass(Registry);
   initializeReassociateLegacyPassPass(Registry);
   initializeRegToMemPass(Registry);
   initializeRewriteStatepointsForGCLegacyPassPass(Registry);
   initializeSCCPLegacyPassPass(Registry);
   initializeSROALegacyPassPass(Registry);

llvm/test/Transforms/MergeICmps/X86/pair-int32-int32.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -mergeicmps -verify-dom-info -mtriple=x86_64-unknown-unknown -S | FileCheck %s --check-prefix=X86
+; RUN: opt < %s -passes='require<domtree>,mergeicmps,verify<domtree>' -mtriple=x86_64-unknown-unknown -S | FileCheck %s --check-prefix=X86
 ; RUN: opt < %s -mergeicmps -verify-dom-info -mtriple=x86_64-unknown-unknown -S -disable-simplify-libcalls | FileCheck %s --check-prefix=X86-NOBUILTIN
 
 %S = type { i32, i32 }
 
 define zeroext i1 @opeq1(
 ; X86-LABEL: @opeq1(
 ; X86-NEXT:  "entry+land.rhs.i":
 ; X86-NEXT:    [[TMP0:%.*]] = getelementptr inbounds [[S:%.*]], %S* [[A:%.*]], i64 0, i32 0